Daily consumption of 40 grams of dark chocolate for two weeks can reduce stress and benefit metabolism and microbial activity in the gut, claims scientists based at the Nestle Research Centre.

In a study published in Journal of Proteome Research the Lausanne based researchers said their results show that eating dark chocolate daily reduced stress hormone levels in those who had high anxiety levels.

The authors maintain that there is growing pool of evidence pointing to the potential health implications of dark chocolate constituents, with the flavonoids in cocoa linked to better cardiovascular health through the maintenance of low blood pressure, improved endothelial function, and a reduction in thrombotic, oxidative and inflammatory states.

However, they claim that the mechanisms of action of chocolate bioactive components at the molecular levels are poorly understood, particularly in the case for benefits related to brain health and improvement of stress states where only symptomatic data, such as brain blood flow, are available

Study
The researchers said that, in order to evaluate the metabolic changes associated with dark chocolate consumption they looked at the effects of eating 40 grams of dark chocolate every day for two weeks on blood and urine measures of stress in 30 healthy adults.

They explained that they used nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) to study changes in metabolism, and that the subjects completed psychological questionnaires, to enable them to be grouped into low and high anxiety traits.

Half of the chocolate was eaten mid-morning and the other half was eaten mid-afternoon, according to the study.

The authors stated that they took urine and blood plasma samples from the participants at the beginning, halfway through, and at the end of the two week study.

Results
The researchers said the results show that they were lower levels of stress hormones in the samples at the end.

“Dark chocolate reduced the urinary excretion of the stress hormone cortisol and catecholamines,” they reported.

The authors conclude that subjects with higher anxiety trait had a distinct metabolic profile, and that this profile was indicative of a different energy homeostasis, hormone metabolism, and gut microbe activity, and that dark chocolate also partially normalized stress-related differences in energy metabolism and gut microbial activities.